JTAG provides boundary-scan test solutions

Swindon, UK-based femtocell vendor Ubiquisys is using JTAG Technologies' boundary-scan test solutions for volume production of its ZoneGate product.

The provision of the test solutions is the result of extensive collaboration between the two companies and, by providing test development services and systems for factory testing, JTAG Technologies was able to relieve the burden of developing structural PCB tests.

Femtocell products address the demand from consumers for cost-effective, high-quality 3G coverage in the home, and Ubiquisys' offering introduces a fast and efficient way of opening the Internet to mobile users.

ZoneGate, which is in mass production today at Sony UK Tech, is a single PCB product that architecturally splits into RF circuitry, baseband processing, clock circuits and power supplies.

The baseband processing is achieved using a custom femtocell chip and an FPGA, memory is provided by DDR2 SDRAM and there is also a flash chip.

Pete Keevill, founder and vice-president of engineering, Ubiquisys, said: 'ZoneGate is a relatively compact, mixed-signal design with about 1,000 nets - the majority of which connect BGA-packaged digital components.' For testing purposes, traditional bed-of-nails style structural testing via an ICT was out of the question.

Also, providing dedicated ICT test points would consume a significant percentage of the board real estate and would have introduced significant signal integrity issues (particularly impractical in the RF section of the PCB).

Keevill added: 'Our test strategy therefore is to marry functional testing of the board's RF, analogue and power components with boundary-scan testing of the digital components.

'However, only two of the components on the board are boundary-scan devices, so they need to be able to cluster test several non-boundary-scan devices.' Ubiquisys considered the products from a number of boundary-scan tool vendors and, based on solution suitability and experience residing within the company, selected JTAG Technologies.

Keevill said that of particular merit was JTAG Technologies' 4 TAP controller, as the ZoneGate PCB has two boundary-scan chains, so they are able to test two boards at the same time.

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